COL5A1 and atrial fibrillation: For 2D culture, the level of expression of COL1A1, COL5A1, FBLN1, IBSP, and TNMD was significantly higher in the DAF‐G and g‐DAF‐G groups than Col I group on Day 21, which indicated the potential induction of directing specific differentiation of hBMSCs towards AF cells on DAF‐G and g‐DAF‐G hydrogels (Figure 4b).